The present invention relates in general to sound transmitting equipment, and in particular to a new and useful arrangement for suppressing amplitude peaks in an electroacoustic transmission system, which peaks are caused by spoken stop consonants.
In voice transmission, microphones are generally troubled by those consonants which are formed by a so-called explosion in the articulation, i.e. a sudden release of impounded breath. Such consonants, called stop consonants or stops, comprise the sounds B,D,T and quite particularly P. Upon exposing a microphone to sound from a distance of about 1 cm up to 12 cm in front of the mouth and without providing a satisfactory sound pickup protection, the microphone will always tend to reproduce the stop consonants in a distorted and overaccentuated way. This phenomenon is termed "pop noise", with the pop signal itself being produced predominantly by low-frequency oscillations up to 300 Hz.
Attempts have repeatedly been made to design a microphone wind guard so as to make the pop noise substantially inaudible. Such microphones protected against wind and blow are disclosed in U.S. Pat. No. 4,263,484, German AS No. 17 62 944 and German OS No. 15 62 210. However, these disclosures do not teach how, and to what extent, the wind guard influences the pop of the microphone. Particularly, only mechanical acoustic remedies are provided.
It is known from speech and word formation analyses that while forming a stop, such as P or T, a pause of about 100 ms precedes the following explosive start of the consonant, which pause is a period of quiescence. Details in this regard may be found in the periodical Acustica, Vol. 43, pages 167 to 173, and in the 11th ICA Report, Paris 1983, pages 205 to 208.